1. Field of the Invention
This invention pertains to boat hulls and, more specifically, to boat hulls with outer foam bumpers and methods of manufacturing such boat hulls.
2. Description of the Related Art
Traditional boat hull bumpers provide an external fender system for protecting the hull of a boat. The fender system must provide sufficient protection for the hull of the boat when mooring the boat or bringing the boat along side another boat for boarding while not interfering with the normal operation of the boat. Traditional boat hull bumpers are made of polymeric foam material separately affixed to the sides of the hull with stainless steel bolts and nuts. In most instances, the bumpers appear as separate structures attached to the sides of the hull. When used in salt water, galvanic corrosion occurs between the bolts and the aluminum hull that often results in the bumper detaching from the hull. Because the bumpers are made of foam, they often split and begin to hang downward from the sides of the hull. This, of course, detracts from the boat""s appearance.
What is needed is an aluminum boat hull with a foam bumper that is more securely attached to the sides of the hull than current boat hull bumper designs and has the appearance of being integrally formed into the hull.
It is an object of the present invention to provide a boat hull with a protective bumper.
It is another object of the present invention to provide such a boat hull wherein the bumper is made of foam and is securely attached to the sides of the hull and does not have the detachment problems found in the prior art.
It is another object of the present invention to provide such a boat hull with a bumper system that appears to be integrally formed into the hull.
It is further object of the present invention to provide an economical method of manufacturing such a boat hull with an integrally attached protective bumper.
These and other objects of the invention which will become apparent are met by an aluminum boat hull that includes rigid framing formed on the sides of the hull that creates a plurality of outward extending chambers in which a continuous foam bumper is created around the sides of the hull. The rigid framing acts not only as a mold used to manufacture the foam bumper, but also as a support structure that securely holds and prevents separation or disengagement of the bumpers from the hull during normal use.
In the preferred embodiment, the rigid frame comprises upper and lower longitudinal members spaced apart and attached along one edge to the sidewalls of the hull from the stern to the bow. Disposed between the upper and lower longitudinal members are a plurality of intermediate members. The intermediate members are evenly spaced apart along the entire length of the hull. In the preferred embodiment, the intermediate members are perpendicularly aligned between the upper and lower longitudinal frame members to form a plurality of outward extending chambers along the sides of the hull. At least one passageway is formed on each intermediate member so that liquid foam material poured into one chamber also flows into an adjacent chamber.
Attached to the outer edges of each longitudinal member is a perpendicularly aligned anchor plate. Each anchor plate is centrally aligned on the outer edge of the intermediate frame member and smaller in width and height than the chambers thereby partially enclosing the outward extending chambers. Optional longitudinally aligned stiffeners may also be attached to the upper and lower longitudinal frame members to provide additional support and stop surfaces for the first foam layer discussed further below.
During the manufacturing process, foam material is poured or sprayed into the chambers until all of the chambers on one side of the hull are filled with foam to create a first foam layer. Sufficient foam material is poured into the chambers until the top and bottom surfaces of the upper and lower longitudinal members, respectively, are covered and the entire intermediate frame members, the anchor plates, and the stiffeners are imbedded therein. After curing, the first foam layer is relatively hard and may be manually shaped to a desired profile. After the first foam layer is created, an optional layer of fiberglass is formed over the outer surface thereof. A second, flexible foam layer is then formed or molded over the fiberglass or first foam layer and around the exposed upper and lower surfaces of the upper and lower longitudinal members. An outer pigmented hardening layer is then applied over the second foam layer so that the bumper is the same color as the hull or the hull trim.
In summary, the upper and lower longitudinal frame members, the intermediate frame members, the anchor plates, and the stiffeners, act as a mold for the first foam layer. These components also act as support structures to securely attach the bumper to the hull and as protective structures that prevent separation from the hull. The second foam layer acts as a protective layer over the inner foam and the exposed surfaces of the frame members.